Insulating confined spaces



April 1948. c. c. HERITAGE 2,439,602

INSULATING CONFINED SPACES Filed March 2, 1943' :s Sheets-Sheet 1 I v 4/fwz/emor Ufa 2% Cf reaye .22 iffarleqy c. c. HERITAGE INSULATING,CONFINED SPACES Apr-H13, 1948.

Filed March 2, 1943 3 ShetS-Sheet 2 lfforizey April 13, 1948. 9c. 0.HERITAGE 2,439,602

- INSULATING CONFINED SPAQES Filed March 2; 1945, .3 Sheets-Sheet 3 ffar674752 7- gage Patented Apr. 13, 1948 Clark 0. Heritage,Cloquet,,.Minn.,, assignor to Wood Conversion Company, Cloquet"; Minn,a:

corporation ofDelaware Application-March 2, 1943, seriatNm amass Claims;(01. -101) The present inventionrelatesto the placement or particles ofthermal insulating; material to build up a thermallyinsulatingintegrated mass of such material ina confined-space. Inparticular it relates to carrying the material in agaseousyeh'icle(hereinafter referred, to again); to .a deposited growing mass ofsuchparticles formed by deposition of particles from the vehicle.

plates completely confining aspaceto be so. filled withinsulationmaterial, whereby to define the formof the mass to be produced,Thespacelmay be provided substantially completely by-or within existingarticles. Howevenras requiredlor desired for/the purposes of theinvention, the spacelto be filled is completely defined by boundingfacial Walls having essentially some filtering area for exhausting thegas in which particles of' themsulating material are introduced, andhavingessentially in the arealof the confining. Walls, one or more inletareas for introducing the gas containing the particles, eachsuch inletarea being essentially in and a fraction of aconiiningwall In generalaspect the invention contem- 1 or face in amanner analogous to therelation mits-the form ofthe space to be complex, or

angulanand not limited to. panel-form spaces. Thus, the vehicular streamof gas is introduced at aldifierential pressure, relative to thepressures at inlet area and at filtering area, and at such a velocitythat the particles suspended in the gas are carried with turbulenceinsidethe space to all portions ofthe-space remote from inlet area;

and-that the differential pressure. packs the deposited mass to aconsolidated body filling the spacewhile saidpressure of the gasstreamis maintained to and-,if desired, even after the complete fillingof the space.

The inventionis applicable in many fields, for examplain packing .fiberor other insulatinglmaterial into carboys to protect-and insulate thefiaks of. liquid t e W W its I Presently preferred use is in insulatingthe doors and cabinets of refrigerators, such as are used in homes.

In the, field of artificial refrigeration, high standards for insulationinl domestic andother refrigerators havedevelopedinorder to minimizeheat'vlos s heat loss addsito the cost ofToperationt, Considerabledifficulty has been encountered in the commerciall development: ofrefrigerator insulation in parallel with thedevelopment of domesticartificial refrigeration. Along with standards and .for low heat a loss,low cost oi insulating material and of insulating proc ass-areimportant, as-are uniformity in. each cabinet andl from. cabinet tocabinet in apmdnctmnimei a. a

In addition, there. is. the .problem of permahence, injlfwhich' 5resistance I meani of packed bulk insulation is most important.Suchiresistance can be attainedhbyl increasing the density or" packing;with which heat? leak or heat. conductance increases asaa'generalrulainrthe, range encountered refrigerators. It is, therefore,

i'rnportantlto-minimize" density; consistently with acceptable-resi'stance. to settling and acceptable insulating value. All thesefactors leadltoaneed forlalprocesswhichis subject to control for meet-In. the prior. art there. has been no low-cost process for packing aspecified'material uniformly and integrally intola cabinet, anduniformly from cabinetjt'o cabinetiinlaproductionline,a The presentinventl'oinl provideslsucha process, and so usedfitgiyes'reproduciblelresults with any reproducible material; Vegetablefibers such as from Wood may readily be produced from timeto time withreproducible properties within given specifications, andv withlsuchimaterial and with" the present. invention a low-cost process foruniformly, and insulating spaces, such as thoseinlreii'i-gerators;becomes available to the manufacturers refrigerators. Reference is madeto my. copending application Serial No; 33fiA95jlfiledsMay 22,-l940',,now Patent No.v2',3 25,- 055, issuediJuly. 7," .1943; describingreproducible fibers whichgarea useful as. particles for practice of. therp resentilihyentionn a The; present-application. is one of a series ofmylcofiled. applicatibnslserial. Nosi47'7 751; 477-,- 7523. 4717:75314W;7.54;and 477,7,55; each one of the series being, directed.generically and specifically to a distincttspecies disclosedlin my saidoriginal aDDlicatiomSerialNb. 294L212;

It; isobiectot the; present invention to insulateinteriorwa-llsrta-bodyproviding; an opent'ibat'w n ng the space to be insulated in partby meanstotaremoyable :fixturecontaining either one or both of inletarea and filtering area, and

tween the said dummy and the cabinet, then re-' moving the fixture andreplacing it with the food 1' compartment.

Various other and ancillary objectsandadvan tages of the invention willappear from the fol-'- lowing description and explanation of theinvention given with reference to the accompanying drawings in which:

Fig. 1 represents in perspective half of a refrigerator cabinet andaboveit in perspective half of a food compartment in position to bedropped into place in the cabinet; j

Fig. 2 represents in two parts a dummy for the food compartment, as abox-like fixture and a pipe system which belongs Within the'saidfixture, the base being shown separated for convenience in illustration;1 t I Fig. 3, represents the type of blower and feeding meansthereforwhich is used for connection to the fixture ofFig.2;' J

Fig. 4 represents amodified fixture'as a dummy food compartment, havingbut one inlet conduit and having differently arranged filtering areas,one wall of the fixture being shown rectified to the plane of the bottommerely to faoilitate'the illus- Fig. 5 represents in perspectivea'p'ortion of the refrigerator cabinet of Fig. l filled with insulatingfiber by use of the fixture of Fig. 4; i

Fig, 6 is a fragmentary view in cross-section taken on the line 6--6'of,Fig 4'and Fig: 5, when the fixture of Fig. 4 is in operatingpositionwithin the cabinet;

Fig. 7 is a view in perspective and vertical cross- 4 food compartmentof a refrigerating unit. One of the said openings to the space is usedfor introducing the gas, while the other is blocked oil. The open spaceat the door opening between the cabinet and the food compartment, wherebreaker-strip material is located in the completed refrigerator, isclosed by a fixture or closure provided with filtering area, andpreferably including also some imper forate area. Thus, the gasintroduced passes through the gas-filtering body of insulating materialbuilt up in the space. Then the fixture is removed, and breaker stripused to close the gap. The space between the openings for the unit thushas insulation, which may be disturbed as necessary in makingconnections when installing the refrigerating unit.

section of an inverted carboy casing' with its with insulating material,after removal of the fixture, and after replacing the fixture by thebottle. j In my earlier parent application Serial No. 294,212, theprocess is "described generically and specifically with respect tovarious forms of the space to be filled, and various types ofspace-confining walls, and removable fixtures, having particularreference to variations in the process for insulating domestic typerefrigerators. I These variations include filling-a refrigerator inwhich the food compartment is already mounted, and also in which thefood compartment is not mounted. In the latter case, a fixture in-theform of a dummy for the food compartment is employed, and the fixture isused to provide filtering area, and may be used to provide inlet area.The process is flexible for accommodating it to various types ofrefrigerators, as well as various types of spaces not necessarily thoseof refrigerators. In

the aid earlier application, there is claimed'spe- It is also set forththat the stream is intro-. duced at a differential pressure betweeninlet and filter areas. This may be effected by having atmosphericpressure at either the inlet area, or at the filtering area. Thelatteris preferred for many practical and mechanical reasons. i

In the present application it i likewise intended that thepressureibe adifierential one, but to simplify the description and the illustration,only the preferred one of super-atmospheric pressure at inlet area isspecifically described and illustrated without intention to limit theinvention thereto. Q

After the introduction of the insulating ma terial into the space to beinsulated, especially in a refrigerator, there are numerous mechanicaloperations which may be necessary to complete the article for use orsale. However, theseeform no essential part of the invention, anddetailed description and illustration of them are herein omitted.

The preferred closures or other means having filtering area arepreferably permanent fixtures 'used in a production line, and are inpreferred practice removedafter each use. However, these may be of otherstructure, for example, metal or cloth filters of such character thatthey need not be removed. Whenretained, they may be a permanent part ofthe final structure, covered or 'not. Hence, the'removal of suchclosures is not considered an essential part of the process. But incertain cases it may be included as an essential part of certain aspectsor variations of the invention. l y

The present invention maybe used forfibers, 'fiakes and particles ofother forms. Examples of fibers are hair, wood fiber, vegetable fiber,kapok, mineral wool, glass wool, asbestos, straw, grasses and manyothers. Examples of other materials are flaked paper, exfoliatedvermiculite, inica, ground cork and like materials. Fibers arepreferred, because they mat and felt and produce stable forms in morecomplex variations of the invention where fixtures may be used andremoved. The following illustrations are, therefore, given with respectto wood fiber, such as that according to my said copending applicationSerial No. 336,495, filed May 22, 1940, now Patent No. 2,325,055, issuedJuly 7, 1943, which was developed primarily for use in the presentinvention.

The invention involves the building up of a consolidated gas-filteringbody of particlesiof insulating material introduced as suspended matterin a stream of gas, into a confined space to be insulated;'and'itinvolves'the provision in the confining walls of said space offiltering area to retain the particles and exhaust the gas. The locationof inlet area, the number ofinlet areas,

tat-sate and the" location;. size; and number' of filtering areas "arenot critical I with respect to: any given space. 'Ihisis because the"stream of" gas is-introduced at avelocity to impel the particles-"withturhulenceintdthe" space 'and to-all parts-"ofthe space; The greater theshortest i distance from inlet area to filtering-area; the thickeris thebody of insulating material through which gas must pass" to exhaustiTherefore; for practical convenience, ,it is desirab'leto havefilteringarea close-to; or-even adjacent toinlet' area; Experi'-.

ence has shown that" because of the" turbulence; the particlesmay-'deposit in regions someoi which are adj acent' t'o filtering area; andothers of 'which are remote from' both" inlet'area and filtering area.-Theresulting deposit grows towardthe'inlet area; andto orthrough theinlet area: In such case; the-filtering area close tooladiecent inletareafacilitates the deposition of tha last-depositedmaterial; Theconditions establish acomplexity" of air-' currents which change astheremaining spaceto* be filled changes: Gyclcnic currentshave beenobserved which tend to: throw carried particles centrifugallyout-of the-local 'a-irstream'and-depositthem brcentrifugal forceand in the mannerdescribed. Also directdeposition by filtration has been observedasoneofthe-resulting actions-to deposit theintroduced particles.

In Fig; 1* there is illustrated a refrigerator cabinet anda foodcompartment therefor lifted out of said cabinet. The cabinet comprises abox=like steel form' Ill havingaback HgShOWIl in-liorizontal positionbut normally being verticalttwo refrigerator sides" 12; refrigerator topI3, cabinet bottom- I4 and" asupporting housing 'I he' food 'compartmentis generally designated 2:0 It: abaclcpanel 21; sides 122 top 23, bottom24; an opening-25 in the back panelifor use in connectionwitharefrigerating unit to. be insertediintheioodficompartment: Thefood'compartmenttisof a si-ze to' fittwithin the flange I551 The lip l5receives screwstby on the-cabinet which breaker strip materialissecured. to. it,

and to the walls of the food compartment, at

the ten thereof; to: close agap between them. This provides space allaround the food: compartment' to receiveinsulation, which space alsohas-aboxelikeform;

According to thepresent invention, the food compartmentiis not withinthe cabinet when. the insulation-is placed; Rather, there is providedas. fixture which is: a substantial: dummy for the? foodcompartm'ent.withzrespectto. the faces cnthefood compartment which areto contact the 'insulation; Preferably; the likeness is exact, but if'it deviates, it: is preferred that-the'dummy provide; thicker spacethan. is. provided by the f and: compartment, whereby. the: food icompartment can compress the deposited. insulation. However, the?dummymaso b'e larger in these respectsyin the caseswhere the depositedmass expands..- slightly= upon: removal of L the dummy. Suchaexpansionoccurs with:deposited wood fiber, andfiifi ist greatestiif: removal ofthe .dummy occurseimmediately arten deposition. Ifiith -e :wood

. 6 fiber-is" allowed to stand in the compressed 'state of originaldepositicnithe" initial elasticity; to expand is tOalarge degreelost byrearrange ment of the fibers into a more thoroughly felted form.

In the present description it is considered that the dummy is the samesize as the food compartment in the said respects, merelytdsimplify thestructures tobeillustrated. i

Fig. 2 shows such a dummy fixture,,described in my earlier: parentapplication Serial; No. 294,212.. ,As therein described; it" wasdesigned for use'in arefrigerator cabinet at either topor bottom ofwhich therewas notspace-tobe insulated adjacent the food compartment.Hence, one illustrated" wall" ofitheifixture is shown-as imperforate. Ithas been. usedfin axreii'igerator where ,the insulation abovethe food.compartment is solid] b'oard,-asyofffiber or cork,,to. give support toheavy mechanism locatedj'abovejitiin the cabinet body. However, such afixture-islalso useful where there is space adjacent such imperforatefixture Wall to be insulated by the present invention. Theprocess issuch that-thematerial WilLdepOsit behind all the:walls oftherillustrated fixture, so longas there-isinlet-areaandfilterin area inthe Walls confiningxthe whole space toib'ei insulated. V

In Fig. 2 there is represented a box-dike fixture 351 which in form isasubstitute forthefood compartment 20' to define the same insulatingspaces inside the cabinet. H], betweenthewalls of thefixtureandthewallsof the cabinet 'l hewalls ofthe fixture aredesignated: end .31, end 32,;bottom 33, and-sides,;3li and 35.,The-pan'e1S -33-, 3 l; and 35- have two inlet v areas. respectively 36.-and 31, 38 and 39, and Ml an'd 4|. Theend paneLBZ hasone i inlet.opening, 42; A; complex: unitary, pipe fixture is. shown in perspectivein-Fig. 2,- Which is illustrated. asiremoved from the box.- fixture 30,of which; it isractually a part built into it; The pipe fixturehasagmainfeedtline 43, for examplaof 4-inch diametersheet metal pipe, with 3-inchdiameter,take-offstdesignated by: numerals already assignemto the feedopenings. Either end or both-endsqofi'the 'main feed line -43 may beused to admit air carryinginsulating material. One: end. 44-i$$hQWRascIosed;

Each panel has a ,closed or.- imperforateperipheral area forming a frameandithe:framewpening may be screened, except where; there is afeedopening or inletiareal Imdetail thepanels; alliexcept panel 3|, have.screen areas; of; wire c1oth45. In the actual-construction; the ends ofth feedpipes are secured -to-thescreens, for

attachment to a fiber-air supply; .andzforremoval.

from the integralfelted jacketformed about it in the cabinet.

When the fixture is withdrawn, the peripheral:

space is filled with a box-like unitary. mater body which isself-supporting: with the fixture withdrawn. With simple precautionsthe' food compartment is" then inserted and secured: in final position.

The following illustrates means. for blowingparticles to the fixture;Consider. the apparatus of Fig.3, having a fan-type blower 45; It-has aconduit 46 for entry of air; into whichhberis six inches diameter andconnected 430- a space to-be filled. The fands-operated at 3 R. P. M. bya 15 H. 2. motor of 1800 R. P. M. Running idle, (connected and operatedbut no fiber fed), the measured pressures are as follows:

The blowing system was used to fill a space A full, then again to /zfull, then to full, and then to 100% full, with measurements of thesystem (idle) at each stage. The measured values are combined in TableII with values taken from Table I and are in the same units as those inTable I.

.Table II Measured in pipe 47 Empty 34 full 34 full full Full It isnoted that under conditions where the exit is wholly or to a degreeblocked, as when the space is full, there is a back pressure encounteredat the inlet to the centrifugal fan.

The back-pressure is an important feature of the use ofsuper-atmospheric pressure feed, with apparatus permitting backpressure. Consider in Fig. 3, that the fan may run while the feed line41 is open. A momentum is established into pipe 41. As this is blockedoff, the moving stream is retarded, at first in part, and fibergradually fills up the inlet conduits. A window (later described)indicates this and the process may be stopped. If not stopped, the backpressure at the inlet blows fiber back in pipe 46. Thus; fiber fed intothe inlet will also be blown out the inlet. The appearance of back-feedor back-pressure is an indication of the final status of being filled.

Many factors influence the result, and practically it is necessary toarrive at standard conditions for the particular equipment used, and thejob at hand. For example, it has been found to .be a general rule thatthe faster the fiber is fed, the less the density of the mat obtained.However, this rule is limited to a very short period of time. In onetested instance the feeding time for the space was varied from fractionsof a. minute to several minutes. The curve of density has been plottedvertically against feeding time plotted horizontally. The curve risesrapidly, and at about 25 seconds it begins to flatten out. In about 60seconds it has reached a maximum density. Such curves were obtained withdifferent fan speeds, and it was found that high speeds (greater kineticenergy to fiber) at the same feeding time gave higher density mats. Byconstructing such curves from experimental procedure, the conditions formost efficient operation and for uniform operation may be easilydetermined.

Fig. 4 represents a second and a preferred form of fixture in which bothinlet area and filtering area are more limited, and imperforate area ismore extensive. Simplicity of fixture structure is evident, andfiltering area is arranged with respect to the more limited inlet area,to secure good formation and stability of the deposit, when of woodfibers, against collapsing on removal of the fixture. r V

Fixture of Fig. 4 has 5 panels, including bottom 50, and two short sides5| and 52 and two long sides 53 and 54. The inlet area 55 is in thecentral part of bottom 50, and is connected to fiberair conduit 56. Atthe corners of the bottom are small triangular filtering areas 51 ofscreen wire. Each of the fixture side walls has like triangularfiltering areas 58 of screen Wire adjacent the areas 51. At the top ofthe side walls of the fixture are disposed near each corner narrowhorizontally elongated screen areas 59. On the longer side walls 53 and54, there are in the vicinity of the center, two narrow verticallyelongated filtering areas 60 and 6|, spaced apart. The function of theseis to vary the fiber formation from that which would result fromomission of the areas 60 and 6!, whereby a reinforcing formation occurs.This is described in the copending application of Pauley, Serial No.439,678, filed April 20, 1942, wherein the same fixture is illustratedand specifically claimed. A window 560, is shown in the conduit 56 toindicate over-filling by the appearance of packed fiber at the window. 7

Fig. 5 illustrates the nature of the fiber deposit formed in the cabinetIll, using the fixture of Fig. 4. The areas formed adjacent filteringarea are shown by stippling, except the areas formed adjacent screens 60and 61. The latter areas in the mat are designated 6| and 62. Screenareas 69 and BI tend, as do other screen areas, to cause the deposit togrow away from them, and they also cause an accumulation of fines to actas reinforcement. The lines of growth give a grain to the deposit and bymixing the grain by coaction of the horizontal and vertical areasillustrated, the vertical walls of large area in the final deposit arestronger and do not collapse.

Fig. 6 is a fragmentary section on line 6--6 of Figs. 4 and 5, showingthe wall IU of the cabinet, screen 65 of the fixture, imperforate sidewall 54 of the fixture, and fiber 62 heterogeneously arranged and morecompact adjacent screen area 60, and a grain extending away therefrom,the drawing being indicative rather than exact.

Filtering area is' not essentially limited to a removable fixture, inpracticing the invention, andmay be located anywhere in the total areaconfining the space. Thus, in Fig. 1, a hole 28 in wall l4 forconnections to the refrigerating unit may be temporarily covered byscreen 29.

, A possible modification of the process is to use the fixture Fig. 4with the inlet area thereof blocked off or removed, and replaced byinlet area on the cabinet. Where there is anopening H5 in the cabinet,which in Fig. l is shown as closed by the platform I! beneath it, theremay be an inlet opening provided in the platform. The opening l6 may beplaced over this inlet area in the platform. The results will be thesame, since it is immaterial in which direction the air stream moves asit enters the back panel space between the back wallsof the cabinet andthe fixture.

The. invention is not limited to refrigerators and has numerousapplications wherein dummy fixtures may be employed. Figs. 6 and 7illustrate but one of these different. fields. In Fig. 7 the box 10illustrates the casing of a carboy in inverted position, with the bottomremoved, on which bottom a, flask or bottle normally rests. There isshown in the box, a unitary fixture H which is I substantially adummyfor the. major ternal fl'ange l fitting the casing :and located atthe level for the bottom of Itheibottle, At the region wherethefiangejolns theqbody, there are plurality of wire screens 16 formingfiltering area. At the center is aeonduit 11 secured -by braces 18to'the body '12. The -conduit -branches intortwo parts -1-9' and-8UwhichtermihaLteatdnlet areas ill and 82m thevicinityor the shoulders 13.

ln use a stream ofair in which fiber orthe like is suspende'd is blownin-via-conduit IL-at -a high velocity creating a turbulence of air andparticles in the confined space, and carrying particles to all portionsof the space. Particles pack against the filters 16 and a deposit grows,filling all the space at least to the inlet areas 8| and B2, and eveninto the conduit if blowing is continued. The fiber or other body isdesignated 83.

Then the fixture H is withdrawn (see Fig. 8), exposing hole 85 in thecasing (normal top), which hole is large enough to receive the mouth 86of bottle 81, which is shown in position replacing the removed fixtureH. Then means is inserted which spaces the bottle laterally from thecasing sides and from the casing floor. Pref erably, this spacer as tothe casing floor is insulating and cushioning, and a thick pad, or fiberboard 88 is suitable. Blocks of wood, fiber board, or other material,89, for lateral spacing, may be suitably secured in the casing, as bybeing mounted to the board 88. Then the floor 9!] of the casing issecured in position.

It is pointed out that, if the space occupied by the fiber board 88 wereby some modification of the process blown to a density of the indicatedmass 83, it would be subject to compression by the weight of the filledbottle in upright position. Dropping of the bottle from this cause wouldaffect the packing 83 in the vicinity of the shoulders of the bottle.

Although I have shown all the inlet area located in the various fixturesillustrated, it is to be understood that this is only the preferredpractice. Inlet area to the space may be one or more areas and belocated anywhere in the walls, and the same is true of filtering area;but in order that the fixture may have a function for the process,either inlet area or filtering area isprovided in the fixture,preferably both, and pref erably all the inlet area and all thefiltering area.

The use of a fan is preferred for the reason that it is a means ofunfelting the fibers to substantially individual fibers. It is this formwhich gives the belt results. However, broadly, the fibers need not becompletely unfelted, and may be in clusters or small aggregates. Use ofother means, such as vacuum 0n the screen end, or feeding fiber directlyinto a current of air, is conducive to providing such loose aggregates,rather than individual particles of fiber. The important point is thatthese are not under mechanical pressure to felt them, and they tend tounfelt in process.

The terms screening means and filtering area" as used herein or in theclaims refer to an area with any effective lattice or perforated memberwhich acts as a screen to filter particles from the carryin gas, and itis to be distinguished from a member porous to air and from a crack oran elongated slot.

The location and size of filtering area relative to inlet area, and thevelocity of the stream of gas, are all such that particles areintroduced withiturbulence innlhportions ofithespace to befilledrand'pack therein.

Numerous modifications of lthe invention are eontemplateddn the appnded: claims.

I claim: n 1- Themethod which comprisesqinsertingan'einsulation-:fnrmingmaterialtwhich are capablero'f paekin itoiform a {consolidatedgas-filtering insulating body thereof and turbulently filling said spacewith said suspension, simultaneously separating said particles from saidgas and venting the gas from said space at one or more predeterminedlocations in the defining walls of said space until said space is packedwith particles in the form of said insulating body, and then withdrawingsaid fixture from said casing.

2. The method which comprises inserting a removable fixture into acasing through an opening therein and thereby defining a space by theexterior walls of said fixture and the interior walls of said casing,sealing said space against substantial leakage, introducing into saidspace at one or more predetermined locations a gaseous suspension ofparticles of thermal-insulation-forming material which are capable ofpacking to form a consolidated gas-filtering insulating body thereof andturbulently filling said space with said suspension, simultaneouslyseparating said particles from said gas and venting gas from said spaceat one or more predetermined locations in the walls of said fixtureuntil said space is packed with particles in the form of said insulatingbody, and then withdrawing said fixture from said casmg.

3. The method of insulating a refrigerator which comprises inserting aremovable fixture having substantially the size and shape of the innerfood compartment into the outer casing of a refrigerator through thedoor opening of said.

casing, sealing the intermural space defined by the inner walls of saidouter casing and the walls of said fixture against substantial leakage,introducing into said space from one or more openings in the walls ofsaid fixture a gaseous suspension of particles ofthermal-insulating-forming material which are capable of packing to forma consolidated gas-filtering insulating body thereof and turbulentlyfilling said space with said suspension, simultaneously separating saidparticles from said gas and venting gas from said space at one or morepredetermined locations in the walls of said fixture until said space ispacked with particles in the form of said insulating body, withdrawingthe fixture from the outer casing, and mounting in the resulting cavitya food compartment to be insulated by said body.

4. A removable fixture to be confined within a casing for depositingparticles of insulating material in said casing and against said fixtureas an insulating body, said fixture comprising insulation-confiningwalls including one or more foraminous areas at predetermined locationsacting as filtering means to hold said particles and vent gas, andhaving one or more openings at predetermined locations for dischargingto the exterior of said fixture, and pneumatic conduit means terminatingin said one or more dischar openings.

5. A removable fixture to be confined within a casing for depositingparticles of insulating material in said casing and against said fixtureas an insulating body, said fixture comprising insulation-confiningwalls including one or more foraminous areas'at predeterminedlocatiorisactin as filtering means to hold said particles and vent gasand having one or more openings at predetermined locations fordischarging to the exterior of said fixture, there being at least oneinsulation-confining wall containing at least one foraminous area and atleast one discharge opening, and pneumatic conduit means terminating insaid one or more discharge openings.

CLARK C. HERITAGE.

REFERENCES CITED The following references are of record in the file ofthis patent: 1

UNITED STATES PATENTS Date Manning Aug. 18, 1936

